ITR: Efficient Self-Organizing Content Distribution Network for Scalable Video Streaming Services

作为IP组播的继承者，应用层组播和覆盖网络已经成为当前互联网中的两项非常重要的技术，它们有望为大规模互联网用户提供一个高度可扩展的信息并发传递平台。本课题以下一代覆盖网络为研究对象，研究如何构建一种分布式、自组织的实时视频流内容分发体系结构。与以前的方法不同，我们的工作不依赖于延迟作为距离的度量，而是利用现有Internet的拓扑和路由结构来计算距离和创建局部拓扑。利用对每个副本服务器邻域的拓扑感知发现，节点构建用于复制静态内容的高效网格，并构建用于实时流直播视频素材的自组织组播覆盖树。要特别注意确保整个体系结构具有高度的可伸缩性，并且适合在现有的Internet上实际使用。一旦安装，建议的内容分发网络(CDN)中的每个节点自动发现其在互联网中的位置，连接到CDN结构的控制树，并在其邻居中找到其他节点。控制树中的信息包含由CDN网络的节点独立发现的因特网的所有视图的可伸缩聚集。使用该控制树，节点可以快速构建到达主数据服务器的一组重叠的邻域网格。到达的终端用户基于他们在互联网中的位置以及各个缓存节点已经发现的网络集群，被有效地定向到最近的缓存。为了避免分组丢失和控制多播树分支上的流，我们研究了新的视频流拥塞控制方法，这些方法允许流畅地播放并在网络延迟反馈的情况下保持稳定。CDN作为现有网络基础设施的重要组成部分出现，已经改善了许多互联网下载的响应时间和吞吐量。未来支持视频流的CDN将提供一个可扩展的平台，向最终用户分发现场直播和预先录制的视频节目，并将极大地提高社会目前传播信息的能力。拟议的研究活动将纳入网络课程课程。这将使学生深入了解与对等网络和内容分发网络相关的架构设计问题。

As successors of IP multicast, application-layer multicast and overlay networks have become two very important technologies in the current Internet that promise to provide a highly scalable platform for concurrent delivery of information to large groups of Internet users. This project focuses on next-generation overlay networks and studies the problem of building a distributed, self-organizing content distribution architecture for real-time video streaming services. Unlike previous approaches, our work does not rely on delay as the metric of distance, but rather utilizes the topological and routing structure of the existing Internet to compute distances and create local topologies. Using topologically aware discovery of the neighborhood of each replica server, nodes build efficient meshes for replication of static content and construct self-organizing multicast overlay trees for real-time streaming of live video material. A special attention is paid to making sure that the entire architecture is highly scalable and suitable for practical use over the existing Internet. Once installed, each node in the proposed content distribution network (CDN) automatically discovers its location in the Internet, attaches to the control tree of the CDN structure, and finds other nodes in its neighborhood. The information in the control tree contains a scalable aggregation of all independently discovered views of the Internet by the nodes of the CDN network. Using this control tree, the nodes quickly build an overlapping set of neighborhood meshes that reach the main data server. Arriving end-users are efficiently directed to the nearest cache based on their location in the Internet and network clusters already discovered by the individual cache nodes. To avoid packet loss and to control the flows along the branches of the multicast tree, we investigate new congestion control methods for video streaming that allow smooth playback and remain stable under delayed feedback from the network. CDNs emerged as a crucial part of the existing web infrastructure and already improve the response time, as well as the throughput, of many Internet downloads. Future CDNs that support video streaming will deliver a scalable platform for distributing live and pre-recorded video programs to end-users and will greatly improve the current ability of the society to disseminate information. The proposed research activities will be integrated in the network course curriculum. This will enable students to gain deep understanding of the architectural design issues related to peer-to-peer networking and content distribution networks.